Bandy W D, Irion J M
Department of Physical Therapy, Health Sciences Center, University of Central Arkansas, Conway 72035-0001.
Phys Ther. 1994 Sep;74(9):845-50; discussion 850-2. doi: 10.1093/ptj/74.9.845.
To date, there are no reports comparing duration of static stretch in humans on joint range of motion (ROM) and hamstring muscle flexibility. The purpose of this study was to examine the length of time the hamstring muscles should be placed in a sustained stretched position to maximally increase ROM.
Fifty-seven subjects (40 men, 17 women), ranging in age from 21 to 37 years and with limited hamstring muscle flexibility (ie, 30 degrees loss of knee extension measured with femur held at 90 degrees of hip flexion), were randomly assigned to one of four groups. Three groups stretched 5 days per week for 15, 30, and 60 seconds, respectively. The fourth group, which served as a control group, did not stretch.
Before and after 6 weeks of stretching, flexibility of the hamstring muscles was determined by measuring knee extension ROM with the femur maintained in 90 degrees of hip flexion. Data were analyzed with a 4 x 2 analysis of variance (group x test) for repeated measures on one variable.
The data analysis revealed a significant group x test interaction, indicating that the change in flexibility was dependent on the duration of stretching. Further post hoc analysis revealed that 30 and 60 seconds of stretching were more effective at increasing flexibility of the hamstring muscles (as determined by increased ROM of knee extension) than stretching for 15 seconds or no stretching. In addition, no significant difference existed between stretching for 30 seconds and for 1 minute, indicating that 30 seconds of stretching the hamstring muscles was as effective as the longer duration of 1 minute.
The results of this study suggest that a duration of 30 seconds is an effective time of stretching for enhancing the flexibility of the hamstring muscles. Given the information that no increase in flexibility of the hamstring muscles occurred by increasing the duration of stretching from 30 to 60 seconds, the use of the longer duration of stretching for an acute effect must be questioned.
迄今为止，尚无关于人体静态拉伸持续时间对关节活动范围（ROM）和腘绳肌柔韧性影响的比较报告。本研究的目的是探讨腘绳肌应保持持续拉伸状态的时长，以最大程度增加关节活动范围。
57名受试者（40名男性，17名女性），年龄在21至37岁之间，腘绳肌柔韧性有限（即，在髋关节屈曲90度时测量，膝关节伸展丧失30度），被随机分配到四组中的一组。三组分别每周拉伸5天，持续时间为15秒、30秒和60秒。第四组作为对照组，不进行拉伸。
在拉伸6周前后，通过在髋关节屈曲90度时测量膝关节伸展的ROM来确定腘绳肌的柔韧性。对一个变量进行重复测量的数据采用4×2方差分析（组×测试）进行分析。
数据分析显示存在显著的组×测试交互作用，表明柔韧性的变化取决于拉伸持续时间。进一步的事后分析表明，30秒和60秒的拉伸在增加腘绳肌柔韧性方面（通过膝关节伸展ROM增加来确定）比15秒的拉伸或不拉伸更有效。此外，30秒拉伸和1分钟拉伸之间没有显著差异，表明30秒拉伸腘绳肌与1分钟的较长持续时间效果相同。
本研究结果表明，30秒的拉伸时长是增强腘绳肌柔韧性的有效时间。鉴于从30秒增加到60秒的拉伸持续时间并未使腘绳肌柔韧性增加，对于急性效果使用更长的拉伸持续时间是否必要值得质疑。
